The present invention relates to a method for the preparation of an immunogenic protein material from Streptococcus zooepidemicus bacteria using an enzymatic digestion and detergent treatment and use of the material as a vaccine against S. zooepidemicus infection in equines.
S. zooepidemicus is classified as a Lancefield Group C Streptococcus. See, for example, Bergey's Manual of Determinitive Bacteriology (8th Ed.), p. 491 (1974). The organism is a recognized bacterial pathogen of horses and is known to colonize the upper respiratory tract, vaginal microflora and skin of horses. Among the disease conditions in which S. zooepidemicus has been implicated or established as the primary etiologic pathogen include endometritis, cervicitis, abortion, mastitis, pneumonia, abscesses and joint infection.
S. zooepidemicus is almost routinely a secondary invader in horses suffering from viral respiratory infections such as equine influenza. This secondary infection may consist of upper respiratory invasion of the sinuses, eustachian tubes or gluttural pouches resulting in a mucoprurulent nasal exudate, persistent fever or lymphadenitis. The incidence of respiratory infections caused by streptococci is quite high in horses but organisms isolated from infected horses are seldom identified as to species. This lack of identification makes accurate estimation of the incidence of S. zooepidemicus-caused infections difficult. However, it is believed that this organism may be the most prevalent of streptococci affecting horses.
S. zooepidemicus is the bacterial pathogen most often isolated from cases of foal pneumonia, and in adult horses, is recognized as the most common etiologic agent involved in pneumonic disease. S. zooepidemicus also appears to be a major cause of abortion in horses and has been estimated to cause between ten and twenty percent of all equine abortions. The majority of internal and external abscesses in horses result from S. zooepidemicus.
At the present time, S. zooepidemicus is treated with antibiotics such as penicillin, tetracycline or gentamicin. However, resistant strains appear to be on the increase. To date, there has been no effective prophylactic agent developed to protect animals from S. zooepidemicus infection.